This invention relates to the sterilization of meat and poultry and, more particularly, relates to a process wherein bacteria on meat and fresh poultry are substantially killed by exposure to CO.sub.2 gas under pressure, followed by rapid depressurization.
In North America, the consumption of low fat chicken and other poultry is on the rise notwithstanding the fact that the presence of salmonella and other potentially harmful bacteria on poultry are common. Accordingly, the reported cases of salmonella food poisoning are also increasing. Improvements in plant sanitation and screening for salmonella loaded carcasses have proven to be inadequate to reduce the incidence of human salmonellosis. Also, the presence of salmonella in minced meat such as hamburger commonly occurs, necessitating careful cooking of the meat to avoid food poisoning.
In the prior art it is known to use CO.sub.2 in sterilization processes. U.S. Pat. No. 3,454,406 issued Jul. 8, 1969 discloses a process in which CO.sub.2 is used in combination with a neutralizing and heating process to destroy bacteria. In a food product, slightly acidified by CO.sub.2, the thermal resistance of spores is reduced; thus a lesser degree of heating is required to kill bacteria than would otherwise be the case.
U.S. Pat. No. 4,361,536 issued Nov. 30, 1982 relating in particular to a method for sterilizing contact lenses discloses a process employing CO.sub.2 gas under pressure, 1.5 atmospheres in this disclosure, followed by a vacuum. It is noted in accordance with this invention that the CO.sub.2 gas displaces oxygen thereby selectively deactivating only aerobic bacteria. Deactivation of aerobic bacteria is further enhanced by providing a sudden transition from positive pressure to a molecular vacuum. However, salmonella is a facultative anaerobe, that is, it grows aerobically or anerobically, and thus is not significantly effected by an oxygen void environment.
It is disclosed in U.S. Pat. No. 1,524,494 issued Jan. 27, 1925 that a positive acid reaction is created when CO.sub.2 gas is purged through moist corks. Carbonic acid, produced as CO.sub.2 gas combines with water, will destroy exposed aerobic and anerobic pathogens if the pH level is low enough and if sufficient time is allowed. Salmonella will not be totally eliminated however, under the atmospheric operating conditions described in this patent.
It is a principal object of the present invention to provide a simple and efficient process for sterilizing meat and poultry, specifically meat and poultry containing salmonella bacteria.
It is a further object of the present invention to kill a wide range of aerobic and anerobic microorganisms.
A still further object of the present invention is the provision of a process to sterilize fresh poultry while concurrently tenderizing said poultry.